Dimensionless quantity

coefficient of friction scale average logarithmic energy decrement g-factor linear strain shrinkage solid angle daylight factor quality factor flattening relative molecular mass metallicity incidence sound pressure reflection coefficient tortuosity partition function quantum number relative humidity guide number conversion transistor count gross tonnage Hamming distance slope color rendering index strain tensor gravitational coupling constant ion transport number cycles per instruction where-to-be-born index Human Development Index relative permittivity state of health resonance escape probability relative atomic mass activity reactivity leaf area index oxidation number Beale number relativistic beta heat capacity ratio optical density compactness measure of a shape count variable state of charge fidelity of quantum states osmotic coefficient electric susceptibility Lorentz factor